The long-term goals of the proposed project are to formulate a better understanding of the biochemical mechanism of synaptic transmission and to clarify the role of cyclic nucleotides in the functioning of the central nervous system (CNS). The objectives of this proposal are to biochemically and pharmacologically characterize the dopamine receptor and in the process determine whether or not dopamine receptors can exist as a subpopulation of receptors, and if in fact they do, purify and characterize them. This study also aims to identify the nature of the dopamine receptor and adenylate cyclase in the dopaminergic regions of the central nervous system. Some of the unaswered questions concerning the dopamine receptor adenylate cyclase complex in the brain which will be considered include a study of how the receptor is coupled to cyclase and how such coupling can be manipulated. Part of this project will also consider the possibility that some dopamine receptors can exist uncoupled to cyclase. The finding that, in vitro dopamine effectively decreases prolactin release from the anterior pituitary with no effect on adenylate cyclase activity provides a comparative tool with which to look at the potential differences in the dopamine receptor which may be coupled to cyclase and the uncoupled receptor. Overall, these data will provide a better understanding of biochemical events in the striatum, and, therefore, may be helpful in the management of Parkinson's Disease and the treatment of schizophrenia.